Patellar Tendonitis (Jumper's Knee)

Patellar Tendonitis is an injury to the tendon connecting your knee cap (Patella) to your shin bone. The Patellar Tendon helps your muscles extend your lower leg so that you can kick a ball, pedal your bicycle and jump up in the air.

Patellar Tendonitis is usually caused by overuse of the Patellar Tendon. People who play sports with lots of squatting and jumping movements are most at risk.

Another cause is abnormal alignment of the lower limbs, such as in Knock Knees or flat feet. These altered postures change the angle between the Quadriceps Muscle and the Patellar Tendon.

Increased tension in the Patellar Tendon may occur during growth spurts, such that the tendon cannot keep up with the growth of the lower leg. In this situation, the tendon becomes too short, causing it to pull on the bottom tip of the knee cap. This condition is known as Sinding-Larsen-Johansson disorder.